JP4986822B2 - Chemical dry processing method of gas - Google Patents

Description

  In the present invention, a gas to be treated is continuously introduced and led out into a reaction tube in which a reaction zone is formed by a packed bed made of a basic sorbent (hereinafter referred to as “sorbent”). It is related with the method of carrying out chemical dry processing by making it contact with a sorbent.

  Here, “sorption” means “when gas is sorbed on the surface of a solid, accompanied by the phenomenon that the gas simultaneously forms a solid solution or a compound” (Hariken Dictionary 5th edition).

  In particular, like organic halogen compounds such as chlorofluorocarbons and sulfur hexafluoride, it is chemically stable (high binding energy) and is difficult to decompose (dissociation) and difficult to perform normal combustion treatment (decomposition rate is low). It is an invention related to a chemical dry processing method of a gas suitable for low).

  The exothermic reaction formulas of organic halogen compounds (fluorocarbons and halons) having a large reaction heat (heat generation amount) suitable for the present invention and sulfur hexafluoride are shown below. As a reference, the exothermic reaction formula is also shown below for hydrogen halides that do not have a large reaction heat.

・ Freon 12: CCl ₂ F ₂ + 3CaO →
CaF ₂ + CaCl ₂ + CaCO ₃ +820 kJ
・ Freon 22: CHClF ₂ + 3CaO + 1 / 2O ₂ →
CaF ₂ + 1 / 2CaCl ₂ + CaCO ₃ + 1 / 2Ca (OH) ₂ +869 kJ
・ Freon 134a: C ₂ H ₂ F ₄ + 5CaO + 3 / 2O ₂ →
2CaF ₂ + 2CaCO ₃ + Ca (OH) ₂ + 1644kJ
・ Sulfur hexafluoride: SF ₆ + 4CaO → 3CaF ₂ + CaSO ₄ + 1344kJ
・ Hydrogen chloride: HCl + CaO →
1 / 2CaCl ₂ + 1 / 2Ca (OH) ₂ + 163.2kJ

  Recently, refrigerators and air conditioners (air conditioners) produced before the start of regulations on the production and use of chlorofluorocarbons from the viewpoint of reducing ozone layer destruction are being discarded. In addition, chlorofluorocarbons and halocarbons (containing chlorofluorocarbons containing bromine) are frequently used for cleaning industrial products, and sulfur hexafluoride is used as an electrical insulating gas in electrical equipment. These halogen-containing compounds are known as greenhouse gases exhibiting a high global warming potential (Freons and halons are further used as ozone-depleting gases).

  Therefore, there is a demand for a method and apparatus for efficiently decomposing used recovered halogen-containing compounds.

  And as a processing method and / or processing apparatus for organic halogen compounds typified by chlorofluorocarbons and halons, for example, the following chemical dry processing methods have been proposed in Patent Documents 1 to 3, for example.

Patent Document 1: “A halogen-containing chemical substance (treated gas) is continuously introduced into and led out from a reaction tube having a packed bed made of a sorbent, and the sorbent is decomposed while the treated gas is decomposed. In the method of decomposing the halogen-containing chemical substance by reaction sorption, a gas diffusion zone and a reaction zone are continuously formed in the packed bed along the gas flow direction, and the reaction zone is set to a decomposition reaction temperature. Maintaining the gas diffusion zone below the decomposition reaction temperature while maintaining, and introducing the gas to be treated into the reaction zone through the gas diffusion zone (Claim 1)
Patent Document 2: “Contains magnesium oxide and calcium oxide, the total content is 50% by weight or more, and [calcium oxide / (magnesium oxide + calcium oxide)] (molar ratio) is 0.67 or less. An organic halogen compound decomposition treatment method comprising reacting a decomposition treatment agent with at least one selected from chlorofluorocarbons, halons, and sulfur hexafluoride at a temperature of 800 to 1400 ° C. (Claim 1, Claim 5)
Patent Document 3: “A reaction part serving as a reaction site between an organic halogen compound and a decomposition treatment agent is provided, and the organic halogen compound and the decomposition treatment agent are continuously introduced into the reaction part. An organic halogen compound decomposition treatment apparatus configured to continuously discharge a decomposition treatment agent from a reaction section, wherein the decomposition treatment agent is the following (a) or (b): Halogen decomposition equipment.

   (a) A decomposition treatment agent containing 50% by weight or more of magnesium oxide.

  (B) Decomposition treatment containing magnesium oxide and calcium oxide, the total content being 50% by weight or more, and [calcium oxide / (magnesium oxide + calcium oxide)] (molar ratio) being 0.67 or less Agent. (Claim 1 etc.).

  Furthermore, as a method for treating acid gas, Patent Document 4 proposes a chemical dry treatment method (dry treatment method) of harmful gas in which an acid gas having the following constitution is rendered harmless by contact with a basic oxide.

“An acidic gas containing hydrogen chloride (HCl) is formed of a packed layer formed of a calcium-based component (Ca component) or a reaction absorbent mainly composed of a Ca component (hereinafter simply referred to as“ absorbent ”). It is a dry treatment method in which hydrogen chloride and other acidic components in an acidic gas are removed by contacting with the reaction zone 38, and the normal temperature of the reaction zone 38 is not affected by the welding phenomenon between the absorbents in a steam atmosphere. A method for dry treatment of acidic gas, characterized by controlling the temperature at the time of contact with the acidic gas to a temperature at which the fusing phenomenon does not occur while the temperature is made higher than the temperature. (Claim 1)
JP 2004-261726 A Japanese Patent No. 3382922 JP 2002-165898 A JP 2004-167403 A

  In each of the above chemical dry processing methods or chemical dry processing apparatuses, the reaction contribution (use efficiency) of the sorbent (solid basic compound) filled in the reaction tube and subjected to the sorption treatment by the reaction zone is extremely high. It was low.

  For example, Patent Document 3, paragraph 0005 states, “When the organic halogen compound is Freon 12, the decomposition treatment agent (sorbent) becomes agglomerated when more than about 0.1 nmol of Freon 12 reacts with respect to n mol of calcium oxide. In addition, when the decomposition treatment agent is made of dolomite, this magnesium oxide has a relatively low melting point like the above-mentioned calcium halide and causes the decomposition treatment agent to be agglomerated. . "

  For this reason, in order not to generate the said agglomeration, it was necessary to prepare a large amount of sorbent compared with the amount of fluorocarbons which are to-be-processed gas. For example, it was necessary to prepare about 9 kg of sorbent (containing CaO) for about 1 kg. In particular, when the reaction zone 38 is formed of a sorbent moving layer, this tendency becomes significant.

  As a result, a large amount of sorbent was generated as waste after use.

  In view of the above, the present invention allows the gas to be treated to be continuously introduced into and led out from the reaction tube in which the reaction zone is formed by the packed bed made of the sorbent, so that the contact between the gas to be treated and the sorbent. An object of the present invention is to improve the use efficiency of a sorbent in a method of dry treatment by reaction.

  In the process of diligently developing to solve the above-mentioned problems, the present inventors have classified the granular post-use sorbent discharged by the screw conveyor 62 or the like into particles having a predetermined particle size or less. When removed, even if the mixing ratio (mass ratio) of the sorbent after use and the new sorbent is 1: 1 or less, the chlorofluorocarbon removal rate (reaction efficiency: sorption efficiency) is the same as that of the new sorbent. Knowing that it is obtained, the inventors have conceived of a chemical dry treatment method and a chemical dry treatment apparatus for gas having the following constitution.

1) Gas to be treated with an organic halogen compound or sulfur hexafluoride in a reaction tube in which a reaction zone having a heating means is formed in a packed bed made of a basic sorbent (hereinafter referred to as “sorbent”). In a method of continuously introducing and deriving as a dry treatment by contact reaction between the gas to be treated and the sorbent,
The post-use sorbent used in the dry process generates abrasion and / or crushing into a granular recycled product,
The regenerated product is classified into a regenerated sorbent from which particles having a predetermined particle size or less have been removed,
The regenerated sorbent is filled in the reaction tube of the same system or another system and reused , and the reaction zone is formed by a moving packed bed of the sorbent, and the regenerated sorbent is Reflux to the reaction tube, and
The sorbent is a CaO-based fired product, the regenerated sorbent and a new sorbent are mixed at a predetermined mixing ratio, and the used sorbent is recycled by abrasion and crushing. It is characterized by carrying out by an inclined screw conveyor provided with a cooling means inclined toward the outlet side .

2) A chemical dry processing apparatus main body provided with a reaction tube having a heating means, the sorbent supply means for supplying a sorbent to the reaction tube, and a post-use sorbent discharged from the reaction tube. A chemical dry treatment apparatus for gas having a treated gas of an organic halogen compound or sulfur hexafluoride, which is provided with a sorbent discharging means forcibly discharging and is capable of continuous operation or intermittent operation ,
A sorbent circuit is disposed between the sorbent discharge means and the sorbent supply means,
The sorbent circulation path includes a regeneration treatment means, and a sorbent new article mixing means is provided downstream of the regeneration treatment means,
In the chemical dry treatment apparatus for gas, wherein the regeneration treatment means is configured to generate wear and / or crushing on the constituent particles of the sorbent after use ,
A classification means is provided on the downstream side of the regeneration treatment means so that the regenerated sorbent can be recovered by excluding those having a predetermined particle diameter or less, and the regenerated sorbent is supplied to the sorbent supply means. Available, and
The regeneration treatment means is a cylindrical inclined screw conveyor provided with cooling means inclined upward toward the conveyor outlet side .

  An example of a chemical dry processing apparatus plant used in the gas chemical dry processing method of this embodiment will be described below.

  Chemical treatment device main body 12, sorbent supply conveyor (sorbent supply means) 14 attached to the chemical treatment device main body 12, exhaust device (exhaust means) 16, and sorbent discharge device after use (Sorbent discharging means) 18.

  The chemical processing apparatus main body 12 includes a reaction tube 22. An upper first hopper 24 is disposed above the reaction tube 22, and an upper second hopper 26 is disposed below the reaction tube 22. The upper first hopper 24 and the upper second hopper 26 are used for primary and secondary storage of the sorbent and stably supplying the sorbent to the reaction tube 22, respectively.

  Further, between the upper end of the reaction tube 22 and the lower hopper 44, a taper connection tube 28 and a bellows connection tube 30 are disposed, and the taper connection tube 28 is provided with a gas inlet (pipe) 32. The taper connecting pipe 28 diffuses supply gas to form a diffusion zone 37. The bellows connection pipe 30 absorbs the thermal expansion in the axial direction of the reaction tube 22 and is an intermediate transition zone for suppressing the start of the reaction that is too early due to the influence of the reaction heat generated in the reaction tube 22. 39 is formed.

  An inner heater 34 is arranged inside the reaction tube 22 and an outer heater 36 is arranged outside, so that a reaction zone 38 is formed. The outer heater 36 is covered with a heat insulating case containing a heat insulating material.

  Although not necessary, the outer heater 36 and the inner heater 34 may be divided into upper and lower parts so that the temperature of the reaction zone 38 (PID control) can be controlled.

  In the present embodiment, the reaction tube 22 does not end near the lower end (end) of the reaction zone 38 (see FIG. 1 of Patent Document 1), but extends to the reaction zone 38, and the extended portion 22 a extends to the lower hopper 44. It is surrounded by. The lower hopper 44 includes a cooling jacket (water cooling in the illustrated example) 46 in the straight cylindrical portion 44 a, forms an exhaust cooling zone 48, and includes an exhaust port 50 on the upper side of the exhaust cooling zone 48. In this configuration, the flow of the product gas in the reaction zone 38 is guided to the vicinity of the sorbent discharge port 44b and then exhausted upward along the outer periphery of the reaction tube 22. As a result, a sufficient spatial distance can be secured between the packed bed (sorbent) 20 and the exhaust port 50, and mixing of fine particles generated during movement of the sorbent into the exhaust can be suppressed.

  The exhaust device 16 is configured such that the exhaust port 50 of the lower hopper 44 is connected to a suction port 56 of a suction machine (blower) 54 and an exhaust pipe 60 in which a bag filter type dust collector 58 is disposed in the middle. ing.

  Further, the used sorbent discharging device (sorbent discharging means) 18 includes, in this embodiment, a screw conveyor (discharge conveyor) 62 connected to the sorbent discharge port 44b of the lower hopper 44, and the screw conveyor. A return conveyor 70 is connected to the outlet side of 62 via a drop chute 68 and returned to a sorbent mixing device 72 described later.

  The discharge conveyor 62 is continuously or intermittently driven by a variable speed drive motor, and can be discharged while cooling the used processing agent by the cooling jacket 64. In this embodiment, the screw conveyor 62 is an inclined screw conveyor that is inclined upward toward the conveyor outlet side in order to promote the regeneration process. It can be expected that wear and / or crushing of the sorbent after use is promoted due to the gravitational action as compared with the case where the screw conveyor is horizontal (see FIG. 1 of Patent Document 1). The inclination angle is usually 15 to 60 °, preferably 20 to 45 °.

  As the sorbent moves after use in the screw conveyor 62, the sorbent particles are brought into frictional or collisional contact with each other, and each surface layer part is partially peeled or crushed. As a result, an unreacted portion or a low-reacted portion is exposed. Thus, the sorbent after use is regenerated (activated).

  The chemical processing apparatus main body 12 of the present embodiment further includes sorbent classifiers (sorbent classifying means) 88 and 94 and a sorbent mixing apparatus (sorbent mixing means: mixing tank) 72. ing.

  In the illustrated example, the sorbent classification device 94 is assembled to the sorbent mixing device 72.

  In other words, the sorbent mixing device 72 includes a recycled product hopper 76, a new hopper 78, and a mixing tank 80. The fixed amount supply conveyors 82 and 84 are connected to the outlets of the hoppers 76 and 78 so that the outlets of the fixed amount supply feeders (screw conveyors) 82 and 84 face the receiving hopper 86 formed at the upper end of the mixing tank 80. It has become.

  A coarse sieve (for example, opening 10 mm) 88 as a sorbent classifier is provided at the intermediate height position of the recycled product hopper 76, the large diameter side product is removed from the system, and the waste conveyor 90 It falls to the entrance side via a fall duct 92.

  Further, a fine sieve (for example, opening 5 mm) 94 as a sorbent classifier is provided at an intermediate height position of the mixing tank 80, and the mixed sorbent on the fine sieve 94 is transferred to the sorbent supply conveyor 14. It is possible to move the small particle size product to the entrance of the waste material conveyor 90 through the fall duct 95.

  When the coarse sieve 88 is a vibrating sieve, the used sorbent can be regenerated by using the vibrating sieve.

  The outlet of the waste material conveyor 90 faces the input port 96a of the waste material container 96.

  The fine sieve 94 is also usually a vibrating sieve. By using a vibrating sieve, the mixing tank 80 can be used for both mixing and classification.

  The return conveyor 70 may be a general-purpose belt conveyor, but if the degree of regeneration is low, a screw conveyor or a vibrating conveyor in which frictional or collisional contact between sorbent particles is promoted is desirable.

  Further, the waste material conveyor 90 is not limited in the type of the conveyor, particularly when the waste material does not have any required characteristics. Usually, a general-purpose belt conveyor is used.

  Next, a chemical treatment method using the above-described chemical dry treatment plant for gas will be described.

  Here, the target gas to be treated is exothermicly reacted with the solid basic compound as described above, and the target elements such as F, Cl, Br, and S are sorbed onto the solid basic compound (reaction decomposition / sorption). If it is worn, it will not be specifically limited. For example, in addition to the above, organic / inorganic compounds containing halogens such as halons, sulfur hexafluoride and hydrogen halides, and halogen gases (hereinafter collectively referred to as “halogen-containing compounds”), and sulfur Examples thereof include compounds (sulfur hexafluoride, SOX, hydrogen sulfide), nitrogen compounds (NOX), and the like.

In addition, as a basic sorbent (solid basic compound), a calcium-based one is usually used, and quick lime (CaO) or calcined dolomite (CaO · MgO) obtained by calcining limestone or dolomite is used. . Depending on the gas to be treated, slaked lime (Ca (OH) ₂ ) limestone (calcium carbonate (CaCO ₃ )), calcium silicate (CaSiO ₃ ) and the like can also be used.

  The particle size of the sorbent is usually 2 to 50 mm, preferably 5 to 20 mm, more preferably 5 to 10 mm (optimum particle size product), although it varies depending on the particle shape. If the particle size is too small, the porosity of the packed bed 20 (such as the reaction zone 38) is low and the gas flow is hindered. If the particle size is too large, gas diffusion into the particles is insufficient. Therefore, it is difficult to obtain optimum processing efficiency (diffusion efficiency and sorption reaction efficiency).

  Initially, a new sorbent is supplied from the new hopper 78 to the sorbent supply conveyor 14 via the quantitative supply feeder 84 and the mixing tank 80. The new material is filled from the sorbent supply conveyor 14 into the reaction tube 22 through the upper first hopper 24 and the upper second hopper 26 of the chemical dry processing apparatus. At this time, the discharge conveyor is also operated and the discharge conveyor is filled with new sorbent. In this way, the packed bed 20 is formed across the upper first hopper 24, the upper second hopper 26, the taper connection tube 28, the bellows connection tube 30, the reaction tube 22, and the lower hopper 44 of the chemical treatment apparatus main body 12. The packed bed 20 results in the gas diffusion zone 37 being formed in the taper connection tube 28, and the intermediate transition zone 39 being formed in the bellows connection tube 30 in the reaction tube 38.

  Next, the inner / outer heater 36 is turned on (ON), and the internal atmosphere temperature of the reaction zone 22 is raised and maintained until it reaches a processing temperature lower limit (lower limit set temperature) or higher. Here, the set processing temperature (sorption reaction temperature) varies depending on the type of gas to be processed and / or the sorbent, but from the viewpoint of decomposition reaction (efficiency), it is usually 250 ° C or higher, preferably 700 ° C or higher. And The upper limit is about 1400 ° C. or less, preferably 800 ° C. or less, from the viewpoints of thermal efficiency and chemical equilibrium, and further from the viewpoint of preventing fusion of the sorbent.

  Here, the set temperature is assumed to be at a substantially central position of the reaction zone 38, for example, at point D to point E in FIG. And although not shown in figure, the temperature measurement point of a thermocouple is provided in each position, and temperature control is performed.

  In general, the gas diffusion zone 37 in the tapered connecting pipe 28 provided with the gas inlet 32 is lower than the decomposition reaction temperature. Here, the gas diffusion zone 37 is usually at a temperature much lower than the decomposition reaction temperature, which is at most 200 ° C. and usually 100 ° C. (for example, point A in FIG. 1). This is because the sorbent (treatment agent) constituting the gas diffusion zone 37 has a very low thermal conductivity and is hardly affected by the temperature of the reaction zone 38. In the present embodiment, the intermediate transition zone 39 formed in the bellows connection pipe 30 is further less susceptible to the temperature effect of the reaction zone 38.

  When the blower (suction means) 54 of the exhaust device is operated (operated) in this state, the gas to be treated (for example, chlorofluorocarbons: hereinafter may be simply referred to as “gas”) is tapered from the gas inlet 32. The gas introduced into the connection pipe 28 is introduced into the reaction zone 38 formed by the reaction tube 22 through the intermediate transition zone 39 formed by the bellows connection pipe 30 while diffusing in the gas diffusion zone 37.

  At this time, the sorbent atmosphere temperature in the tapered connecting pipe 28 is lower than the sorption reaction temperature of the gas to be processed. For this reason, the gas to be treated moves to the reaction zone 38 while being diffused in the sorbent filling gap in the gas diffusion zone 37.

  The gas that has reached the reaction zone 38 is the reaction zone 38. Halogen compounds and the like generated by the reaction with the sorbent are sorbed and fixed to the sorbent, and the generated gas (carbon dioxide gas, water vapor, etc.) is halogenated. It is discharged from the exhaust port 50 as exhaust gas that does not contain etc.

  A gas transition zone (intermediate zone) 39 that is a temperature gradient zone (for example, 100 ° C. or higher and lower than 600 ° C.) exists at the boundary between the gas diffusion zone 37 and the reaction zone 38.

  When the inclined screw conveyor 62 is driven, the sorbent in the reaction tube 22 gradually moves downward due to gravity, and the used sorbent used for the sorption process passes through the lower hopper 44. Then, it reaches the inlet of the screw conveyor 62 and is further regenerated and transferred to the sorbent mixing device 72 via the return conveyor 70 as described above.

  Then, the sorbent regenerated product is introduced into the reprocessed product hopper 76, the coarse particles are removed by the coarse sieve 88, and the sorbent mixing device 72 is used to supply a new sorbent and quantitative supply. Mixing at a predetermined ratio using the feeders 82 and 84, and removing the small particle size product of the mixed sorbent with a fine sieve 94, a regenerated sorbent is obtained.

  At this time, the mixing ratio of the treated sorbent and the new sorbent varies depending on the type of regenerated sorbent and the degree of regeneration. For example, when the sorbent is a CaO-based fired product, the former / the latter (mass ratio) = 1/9 to 9/1, preferably 2/8 to 8/2, and more preferably 4/6 to 6 / 4. When the ratio of the sorbent-treated product is higher, the effective use (use efficiency) of the sorbent is improved. However, when the ratio is too high, the sorption ability of the regenerated sorbent may be unstable.

  The regenerated sorbent thus prepared is returned to the reaction tube 22 via the sorbent supply conveyor 14 continuously or intermittently for gas treatment.

  At this time, as shown in the examples, the regenerated sorbent exhibits a gas sorption ability equivalent to that of a 100% new product even when the amount of new product mixed is close to 1/4. Furthermore, the present inventors have confirmed that the same sorption ability as in the case of 100% new product is exhibited even if the sorbent after use is repeatedly mixed 1: 1 with the new product (4 times). is doing.

  In the above embodiment, the chemical treatment apparatus main body 12 has been described with reference to the example basically the same as the structure shown in FIG. 1 of Patent Document 1, but the chemical treatment apparatus to which the present invention is applicable is described. The form of the main body is not limited to that shown in FIG.

  For example, the gas shown in FIG. 2 of Patent Document 1 is introduced from the lower side of the introduction reaction tube and exhausted to the upper side of the reaction tube. Further, as shown in FIG. 2, the exhaust is passed through the first screw conveyor 62A. The method to be performed, and further to various modes described in Patent Document 1. In FIG. 2, the corresponding parts in FIG. 1 are denoted by the suffix “A” of the same reference numerals, and description thereof is omitted.

  In addition, the present invention does not continuously mix the reprocessed product with the new sorbent as in the above embodiment, but stores the regenerated product and batch-mixes with the new sorbent. May be.

  Furthermore, in the regeneration treatment, the sorbent is stored after use, and the regeneration sorbent is prepared by independent regeneration treatment, classification and mixing. Alternatively, it can be used as a sorbent for a reaction tube of another system. Here, various general-purpose stirring (mixing) devices and crushing devices can be used for the regeneration treatment.

  Next, the comparative tests conducted on Examples 1 to 4 and the conventional example conducted for confirming the effect of the present invention will be described. As the chemical dry processing apparatus used in the operations of the following examples and conventional examples, those having the following specifications shown in FIG. 1 with the sorbent circulation mechanism removed were used.

      Reaction tube 22 ... formed by connecting a stainless steel telescopic tube (250A x 205mm) to a 10B Inconel tube (267.4mmφ x 1400mm). Filling amount: about 800kg.

      Inner heater 34: 12kW (6kW x 2), outer heater 36: 24kW (12kW x 2).

      Lower hopper 44: a stainless steel 20 pipe (508 mmφ × 550 mm).

Screw conveyor for discharge 62 ... Inclination angle: 15 °, cylinder inner diameter 150mm, cylinder length 1580mm, screw pitch 100mm, screw outer diameter 105mm, shaft diameter 65mm, opening 20B steel pipe, rotation speed: 6 ~ 12.5rpm (min ^-1 ).

Gas inlet 32, gas outlet: 1B steel pipe (34.0mm)
As the sorbent (new material), an optimum particle size product of baked dolomite (5 mm on 10 mm sieve classified product: the same applies hereinafter). Further, in the following, “under-sized product” means a classified product that passes 5 mm. The composition of the baked dolomite used in this example is shown in Table 1.

＜従来例＞
上記収着剤新材（至適粒径品）を用いて、運転条件を、反応帯３８を設定温度：800℃、収着剤供給量：90kg／ｈ、フロン供給量：10kg／ｈ（供給フロン濃度：21.2vol％）、吸引空気量：170L／minとして、10時間、フロン２２の収着処理運転を行った。

<Conventional example>
Using the above new sorbent material (optimum particle size), operating conditions, reaction zone 38 set temperature: 800 ° C, sorbent supply rate: 90 kg / h, chlorofluorocarbon supply rate: 10 kg / h (supply) The chlorofluorocarbon 22 was subjected to a sorption treatment operation for 10 hours at a freon concentration of 21.2 vol% and a suction air amount of 170 L / min.

  The post-use sorbent discharged from the discharge screw conveyor in this sorption treatment operation was classified into an optimal particle size product and a small particle size product.

  The fluorine content and the chlorine content were measured for the optimum particle size product and the small particle size product (measured by a gas chromatograph mass spectrometer (GC-MS)).

  Further, exhaust gas was collected after 5 hours from the start of operation, and the concentration of undecomposed flon 22 was measured (measured by GC-MS).

<Example 1>
Using the optimal particle size of the sorbent after use generated in the above conventional example as a recycled material, the recycled material is mixed with a new sorbent material so that the mixing ratio (the former / the latter) = 1/1. Thus, a recycled material mixed sorbent for Example 1 was prepared.

  Then, using the recycled material mixed sorbent, chlorofluorocarbon 22 was subjected to a sorption process in the same manner as in the conventional example, and each item was measured.

<Example 2>
The used sorbent (recycled material) discharged from the screw conveyor for discharge in Example 1 was mixed with the unused agent (new material) so that the mixing ratio (the former / the latter) = 1/1. Using the regenerating agent mixed sorbent prepared in
<Example 3>
The same procedure as in Example 2 was performed except that the mixing ratio of the regenerated regenerated material and the new material (unused sorbent) was 1/3.

<Example 4>
The same procedure as in Example 2 was performed except that the mixing ratio of the regenerated material of the regenerated agent mixed sorbent and the new material (unused sorbent) was 3/1.

<Results and discussion>
From Table 2 showing the results, the following can be understood.

  It can be seen that even with a regenerated material mixed sorbent in which the regenerated material is mixed about three times as much as the new material, the sorption efficiency remains unchanged (both 99.99% or more).

  This is because the fluorine / chlorine content of the sorbent after use is significantly higher (1.5 times or more) in the case of the optimal particle size product than in the conventional example, and the conventional example in the case of the small particle size product. This is also supported by the fact that the examples are almost unchanged.

なお、本発明者らは、３回使用再生材及び4回使用再生材を新材と1／1混合したものを収着剤として使用し、上記と同様にしてフロン２２及びフロン１２について試験を行ったが、同様に99.99％以上の収着効率を示すことを確認している。

In addition, the present inventors used a mixture of three times recycled materials and four times recycled materials with a new material as a sorbent, and tested Freon 22 and Freon 12 in the same manner as described above. It was confirmed that the sorption efficiency was 99.99% or more.

It is a schematic whole block diagram which shows an example of the chemical dry processing apparatus of the gas of this invention. It is a schematic sectional drawing which shows the other aspect of the chemical dry processing apparatus of the gas which can apply this invention.

Explanation of symbols

12 ... Chemical treatment apparatus body 14 ... Sorbent supply conveyor (sorbent supply means)
16 ... Exhaust device (exhaust means)
18 ... Sorbent discharge device after use (sorbent discharge means)
20 ... packed bed 22 ... reaction tube 38 ... reaction zone 62 ... inclined screw conveyor (regeneration processing means)

Claims (2)

A packed bed of a basic sorbent (hereinafter referred to as “sorbent”), in which a reaction zone equipped with a heating means is formed, and an organic halogen compound or sulfur hexafluoride is used as a gas to be treated. In the method of conducting dry treatment by contact reaction between the gas to be treated and the sorbent, introduced and led out automatically,
The post-use sorbent used in the dry process generates abrasion and / or crushing into a granular recycled product,
The regenerated product is classified into a regenerated sorbent from which particles having a predetermined particle size or less have been removed,
The regenerated sorbent is filled in the reaction tube of the same system or another system and reused , and the reaction zone is formed by a moving packed bed of the sorbent, and the regenerated sorbent is Reflux to the reaction tube, and
The sorbent is a CaO-based fired product, the regenerated sorbent and a new sorbent are mixed at a predetermined mixing ratio, and the used sorbent is recycled by abrasion and crushing. A chemical dry processing method of gas, which is performed by an inclined screw conveyor provided with cooling means inclined toward the outlet side . Chemical dry processing apparatus main body provided with a reaction tube having a heating means, the sorbent supply means for supplying the sorbent to the reaction tube, and forcibly discharging the used sorbent discharged from the reaction tube A chemical dry treatment apparatus for a gas having an organic halogen compound or sulfur hexafluoride as a gas to be treated , provided with a sorbent discharging means for performing continuous operation or intermittent operation ,
A sorbent circuit is disposed between the sorbent discharge means and the sorbent supply means,
The sorbent circulation path includes a regeneration treatment means, and a sorbent new article mixing means is provided downstream of the regeneration treatment means,
In the chemical dry treatment apparatus of gas, wherein the regeneration treatment means is configured to cause wear and / or crushing of the constituent particles of the sorbent after use ,
A classification means is provided on the downstream side of the regeneration treatment means so that the regenerated sorbent can be recovered by excluding those having a predetermined particle diameter or less, and the regenerated sorbent is supplied to the sorbent supply means. Available, and
A chemical dry processing apparatus for gas, wherein the regeneration treatment means is an inclined screw conveyor provided with a cooling means inclined upward toward the conveyor outlet side .

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